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RadCAD® is a thermal radiation and environmental heating software. RadCAD® is a module available for use with Thermal Desktop® or stands alone. RadCAD® calculates radiation exchange factors, view factors, for radiation dominated systems such as cryogenic dewars, in addition to capabilities to calculate terrestrial solar heat rates, absorbed direct and indirect environment fluxes.
Innovations by C&R Technologies to the ray tracing process have resulted in an extremely efficient radiation analyzer. RadCAD has also incorporated the progressive radiosity algorithm into heating rate calculations, resulting in even faster performance. Automatic compression and decompression of internal database files minimizes disk usage. Powerful thermal analysis can now be performed using modest desktop computer hardware, exceeding the performance of most UNIX based workstations. Product Overview - An ultra-fast, oct-tree accelerated Monte-Carlo ray tracing algorithm is used by RadCAD to compute radiation exchange factors, view factors, radiation conductors, and heating rates. Innovations by C&R Technologies to the ray tracing process have resulted in an extremely efficient radiation analyzer.
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- Analysis Groups: One of the many powerful concepts in RadCAD is that of a radiation analysis group. When a radiation computation is invoked, it operates only on the currently active analysis group instead of solving the combined case.
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- Articulated Geometry: articulators are modeling objects that can be used to change the position or model geometry. Thermal Desktop has two types of articulators: assemblies and trackers. Assemblies can translate and rotate modeling objects. Trackers are a special type of articulator that rotates model objects based on relative position, perhaps relative to the Sun or a Star. Trackers are useful for pointing solar arrays, thermal radiators, etc.
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- Properties Databases and Aliases: The property databases files store the thermophysical and optical properties. A number of options are available for properties including: temperature dependence; pressure dependence for conductivity; angular dependence for optical properties; phase change; effective emissivity for MLI; and ablation for non-charring ablation and sublimation. The user may opt to change the property databases from one case to another to examine the effects of property degradation (end-of-life), perhaps.
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Property aliases allow the user to specify a name linked to a property. The alias name is used in place of a property and points the property in the database. The property used in a solution can be changed by changing the property associated with the alias. |
FEATURES - CAD drawing methods and high-level RadCAD surfaces including snap-on methods that use CAD drawings as "scaffolding".
- Variable geometry through the use of articulators (assemblies and trackers).
- Solve for form factors, radiation exchange factors, or absorbed fluxes.
- Choice of solution methods: accelerated Monte Carlo ray tracing (MCRT) or progressive radiosity.
- Proprietary advances in Oct Cell technology for amazingly fast computations.
- True curved geometric surfaces.
- Specular and Diffuse surfaces.
- Angular dependent surface properties.
- Full orbital plotting package with both basic and Keplerian input.
- Analysis groups offer significant speed savings.
- Optical Property Aliases help in database management.
- Refraction capabilities for transparent specular surfaces.
- Automatic Oct Cell optimization for determining best subdivision and surfaces per cell criteria.
- Vector List Orbit definition for modeling trajectory orbits.
- Arbitrary source input for modeling IR/Sol Lamps.
- Fast spinning surfaces.
- Symmetry/Mirror planes.
- Automatic restart determination.
- Free Molecular Heating (FMH) algorithms.
- Quick checks to allow for finding surfaces that overlap to aid in radiation model debugging.
- Postprocessing (view factors, RADKs, fluxes, SINDA temperatures, etc.).
Import and Export Capabilities - TRASYS import and export.
- Nevada import.
- STEP-TAS import and export
- IDEAS FD import
- TSS import and export
|  | RadCAD® custom surfaces stretch with the mouse, accurately represent the true geometry, snap on to CAD drawings, and are rapidly solved |  | Full orbit radiation and viewing |  | Easily model radiation-dominated systems |
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Applications: Modeling Solar Concentrating Systems with RadCad
C&R Thermal Desktop® and SINDA/FLUINT offers best-in-class thermal radiation solutions, which are critically important to both space vehicle and solar power system analyses. This tool suite also uniquely offers single- and two-phase thermohydraulics, which means an entire solar energy system can be modeled from the collectors to the steam power cycle or feedwater heat exchangers.
Solar concentrating systems focus the sun’s energy onto a collection system for conversion into electricity. There are several types of concentrator systems: parabolic dish with Stirling-cycle engine, power tower, linear Fresnel concentrators, and parabolic trough concentrators. Many of these systems collect heat into a heat transfer fluid that is used either to boil water, or to preheat the water before it enters a boiler heated by a conventional fuel source.
The latter strategy was recently implemented near Grand Junction, Colorado by Xcel Energy. In that system, a parabolic trough system is used to preheat feedwater to a coal burning power plant, thereby reducing the amount of coal required |
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Parabolic trough: The parabolic trough presents a unique problem for modeling. Estimating the shape of a parabola with faceted surfaces (i.e., meshed surfaces) makes it extremely difficult to accurately calculate reflections. Thermal Desktop overcomes this limitation by including mathematically correct surfaces, such as parabolic dishes and parabolic troughs whose shape can be adjusted parametrically. Such native Thermal Desktop surfaces provide accurate shapes independent of the nodal resolution.
To emphasize this point, the trough shown in the images below is represented by a single thermal node. More realistic resolution is easily obtained as needed to calculate temperature gradients on the reflector, perhaps as caused by imperfect alignment, convection, etc. False gradients on the collector, which result from a faceted representation of the reflector, are not a concern at any resolution with the Thermal Desktop trough surface. |
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Heat Collector Element: At the focus of the parabolic trough is a heat collector element (HCE). The HCE typically consists of (1) an evacuated glass envelope, (2) a steel receiver pipe coated with a high absorptivity and low emissivity coating, and (3) a heat transfer fluid flowing through the pipe. The evacuated envelope prevents heat loss through convection. Occasionally, the vacuum is lost, so parametric modeling in Thermal Desktop can be used to show the effect of heat transfer between the receiver pipe and the envelope. With FloCAD® for creating the thermohydraulic piping network, the analyst can assume the receiver pipe is isothermal about its circumference or can examine the effects of higher resolution about the circumference. Thermoelastic loading, perhaps caused by asymmetric heating of the HCE, could be analyzed by mapping the temperature results to a structural model (independent of the resolution used in the thermal model).
Fluid Flow and Energy Balance: SINDA/FLUINT can calculate the energy transfer through conduction, convection and radiation as well as the fluid flow through the HCE. The solution from SINDA/FLUINT can provide temperatures throughout the system and pressures and flow rates in the flow network. Strengths of the thermohydraulic solutions include two-phase flow and transients (e.g., start-up, shut-down, and control system design). |
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Additional Thermal Desktop, RadCAD, FloCAD and SINDA/FLUINT Capabilities for Concentrating Solar Power Systems
- Accurate curved surfaces for radiation calculations
- Transparent surfaces and solids with refraction
- Mapping of thermal results to structural models
- Receiver pipe
- HCE supports
- Parameterized analyses
- External convection to ambient
- Internal convection between receiver pipe and glass envelope
- Optical properties of the reflector and receiver
- Free molecular heat transfer for near-vacuum in glass envelope
- Diffuse solar load and diffuse sky IR radiation
- Solar tracking for surfaces or groups of objects
- Psychrometrics for condensing air heat exchangers
- Condenser, evaporator, and boiler sizing and simulation
- Phase change materials for thermal energy storage
- Turbomachine components
- Cycle-level analysis of power generation cycles
- Performance map-based descriptions of single- or multi-stage turbomachines
- Steam turbines
- Heat transfer fluid pumps
These capabilities may be used separately for component-level analyses or together for plant-level analyses. Useful Links for Application:Application1 Application2 |
RadCAD® is a thermal radiation and environmental heating software. RadCAD® is a module available for use with Thermal Desktop® or stands alone. RadCAD® calculates radiation exchange factors, view factors, for radiation dominated systems such as cryogenic dewars, in addition to capabilities to calculate terrestrial solar heat rates, absorbed direct and indirect environment fluxes.
Innovations by C&R Technologies to the ray tracing process have resulted in an extremely efficient radiation analyzer. RadCAD has also incorporated the progressive radiosity algorithm into heating rate calculations, resulting in even faster performance. Automatic compression and decompression of internal database files minimizes disk usage. Powerful thermal analysis can now be performed using modest desktop computer hardware, exceeding the performance of most UNIX based workstations.
Product Overview
Property aliases allow the user to specify a name linked to a property. The alias name is used in place of a property and points the property in the database. The property used in a solution can be changed by changing the property associated with the alias.
FEATURES
Import and Export Capabilities
RadCAD® custom surfaces stretch with the mouse, accurately represent the true geometry, snap on to CAD drawings, and are rapidly solved
Full orbit radiation and viewing
Easily model radiation-dominated systems
Applications: Modeling Solar Concentrating Systems with RadCad
C&R Thermal Desktop® and SINDA/FLUINT offers best-in-class thermal radiation solutions, which are critically important to both space vehicle and solar power system analyses. This tool suite also uniquely offers single- and two-phase thermohydraulics, which means an entire solar energy system can be modeled from the collectors to the steam power cycle or feedwater heat exchangers.
Solar concentrating systems focus the sun’s energy onto a collection system for conversion into electricity. There are several types of concentrator systems: parabolic dish with Stirling-cycle engine, power tower, linear Fresnel concentrators, and parabolic trough concentrators. Many of these systems collect heat into a heat transfer fluid that is used either to boil water, or to preheat the water before it enters a boiler heated by a conventional fuel source.
The latter strategy was recently implemented near Grand Junction, Colorado by Xcel Energy. In that system, a parabolic trough system is used to preheat feedwater to a coal burning power plant, thereby reducing the amount of coal required
Parabolic trough: The parabolic trough presents a unique problem for modeling. Estimating the shape of a parabola with faceted surfaces (i.e., meshed surfaces) makes it extremely difficult to accurately calculate reflections. Thermal Desktop overcomes this limitation by including mathematically correct surfaces, such as parabolic dishes and parabolic troughs whose shape can be adjusted parametrically. Such native Thermal Desktop surfaces provide accurate shapes independent of the nodal resolution.
To emphasize this point, the trough shown in the images below is represented by a single thermal node. More realistic resolution is easily obtained as needed to calculate temperature gradients on the reflector, perhaps as caused by imperfect alignment, convection, etc. False gradients on the collector, which result from a faceted representation of the reflector, are not a concern at any resolution with the Thermal Desktop trough surface.
Heat Collector Element: At the focus of the parabolic trough is a heat collector element (HCE). The HCE typically consists of (1) an evacuated glass envelope, (2) a steel receiver pipe coated with a high absorptivity and low emissivity coating, and (3) a heat transfer fluid flowing through the pipe. The evacuated envelope prevents heat loss through convection. Occasionally, the vacuum is lost, so parametric modeling in Thermal Desktop can be used to show the effect of heat transfer between the receiver pipe and the envelope. With FloCAD® for creating the thermohydraulic piping network, the analyst can assume the receiver pipe is isothermal about its circumference or can examine the effects of higher resolution about the circumference. Thermoelastic loading, perhaps caused by asymmetric heating of the HCE, could be analyzed by mapping the temperature results to a structural model (independent of the resolution used in the thermal model).
Fluid Flow and Energy Balance: SINDA/FLUINT can calculate the energy transfer through conduction, convection and radiation as well as the fluid flow through the HCE. The solution from SINDA/FLUINT can provide temperatures throughout the system and pressures and flow rates in the flow network. Strengths of the thermohydraulic solutions include two-phase flow and transients (e.g., start-up, shut-down, and control system design).
Additional Thermal Desktop, RadCAD, FloCAD and SINDA/FLUINT Capabilities for Concentrating Solar Power Systems
These capabilities may be used separately for component-level analyses or together for plant-level analyses.
Useful Links for Application:
Application1
Application2